Experimental Study on a Second-Harmonic Intensity Modulator with Quasi-Phase-Matched Optical Waveguides

A second-harmonic intensity modulator with quasi-phase-matched optical waveguide is fabricated and demonstrated. The domain-inverted structure and proton-exchanged optical waveguides are fabricated on a Z-cut LiTaO 3 substrate. Traveling-wave type Al electrodes are fabricated on the SiO 2 buffer layer. Second-harmonic radiation can be modulated by giving phase mismatch to the second-harmonic generator by using the electro-optic effect. The conversion efficiency of the device is 0.4%/Wcm 2 and the switching voltage is 180 V, when the duty ratio of the quasi-phase-matched grating is 0.4. Modulation is achieved up to about 1 MHz.